org.apache.flink.table.planner.functions.aggfunctions.IncrSumWithRetractAggFunction Maven / Gradle / Ivy

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.planner.functions.aggfunctions;

import org.apache.flink.table.api.DataTypes;
import org.apache.flink.table.expressions.Expression;
import org.apache.flink.table.expressions.UnresolvedReferenceExpression;
import org.apache.flink.table.types.DataType;
import org.apache.flink.table.types.logical.DecimalType;
import org.apache.flink.table.types.logical.utils.LogicalTypeMerging;

import static org.apache.flink.table.expressions.ApiExpressionUtils.unresolvedRef;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.equalTo;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.ifThenElse;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.isNull;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.lessThan;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.literal;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.minus;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.nullOf;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.or;
import static org.apache.flink.table.planner.expressions.ExpressionBuilder.plus;

/**
 * built-in IncrSum with retract aggregate function, negative number is discarded to ensure the
 * monotonicity.
 */
public abstract class IncrSumWithRetractAggFunction extends DeclarativeAggregateFunction {
    private UnresolvedReferenceExpression sum = unresolvedRef("sum");
    private UnresolvedReferenceExpression count = unresolvedRef("count");

    @Override
    public int operandCount() {
        return 1;
    }

    @Override
    public UnresolvedReferenceExpression[] aggBufferAttributes() {
        return new UnresolvedReferenceExpression[0];
    }

    @Override
    public DataType[] getAggBufferTypes() {
        return new DataType[] {getResultType(), DataTypes.BIGINT()};
    }

    @Override
    public Expression[] initialValuesExpressions() {
        return new Expression[] {/* sum = */ nullOf(getResultType()), /* count = */ literal(0L)};
    }

    @Override
    public Expression[] accumulateExpressions() {
        return new Expression[] {
            /* sum = */ ifThenElse(
                    or(isNull(operand(0)), lessThan(operand(0), zeroLiteral())),
                    sum,
                    ifThenElse(isNull(sum), operand(0), plus(sum, operand(0)))),
            /* count = */ ifThenElse(
                    or(isNull(operand(0)), lessThan(operand(0), literal(0L))),
                    count,
                    plus(count, literal(1L)))
        };
    }

    @Override
    public Expression[] retractExpressions() {
        return new Expression[] {
            /* sum = */ ifThenElse(
                    or(isNull(operand(0)), lessThan(operand(0), zeroLiteral())),
                    sum,
                    ifThenElse(
                            isNull(sum), minus(zeroLiteral(), operand(0)), minus(sum, operand(0)))),
            /* count = */ ifThenElse(isNull(operand(0)), count, minus(count, literal(1L)))
        };
    }

    @Override
    public Expression[] mergeExpressions() {
        return new Expression[] {
            /* sum = */ ifThenElse(
                    isNull(mergeOperand(sum)),
                    sum,
                    ifThenElse(isNull(sum), mergeOperand(sum), plus(sum, mergeOperand(sum)))),
            /* count = */ plus(count, mergeOperand(count))
        };
    }

    @Override
    public Expression getValueExpression() {
        return ifThenElse(equalTo(count, literal(0L)), nullOf(getResultType()), sum);
    }

    protected abstract Expression zeroLiteral();

    /** Built-in IncrInt Sum with retract aggregate function. */
    public static class IntIncrSumWithRetractAggFunction extends IncrSumWithRetractAggFunction {

        @Override
        public DataType getResultType() {
            return DataTypes.INT();
        }

        @Override
        protected Expression zeroLiteral() {
            return literal(0);
        }
    }

    /** Built-in Byte IncrSum with retract aggregate function. */
    public static class ByteIncrSumWithRetractAggFunction extends IncrSumWithRetractAggFunction {
        @Override
        public DataType getResultType() {
            return DataTypes.TINYINT();
        }

        @Override
        protected Expression zeroLiteral() {
            return literal((byte) 0);
        }
    }

    /** Built-in Short IncrSum with retract aggregate function. */
    public static class ShortIncrSumWithRetractAggFunction extends IncrSumWithRetractAggFunction {
        @Override
        public DataType getResultType() {
            return DataTypes.SMALLINT();
        }

        @Override
        protected Expression zeroLiteral() {
            return literal((short) 0);
        }
    }

    /** Built-in Long IncrSum with retract aggregate function. */
    public static class LongIncrSumWithRetractAggFunction extends IncrSumWithRetractAggFunction {
        @Override
        public DataType getResultType() {
            return DataTypes.BIGINT();
        }

        @Override
        protected Expression zeroLiteral() {
            return literal(0L);
        }
    }

    /** Built-in Float IncrSum with retract aggregate function. */
    public static class FloatIncrSumWithRetractAggFunction extends IncrSumWithRetractAggFunction {
        @Override
        public DataType getResultType() {
            return DataTypes.FLOAT();
        }

        @Override
        protected Expression zeroLiteral() {
            return literal(0F);
        }
    }

    /** Built-in Double IncrSum with retract aggregate function. */
    public static class DoubleIncrSumWithRetractAggFunction extends IncrSumWithRetractAggFunction {
        @Override
        public DataType getResultType() {
            return DataTypes.DOUBLE();
        }

        @Override
        protected Expression zeroLiteral() {
            return literal(0D);
        }
    }

    /** Built-in Decimal IncrSum with retract aggregate function. */
    public static class DecimalIncrSumWithRetractAggFunction extends IncrSumWithRetractAggFunction {
        private DecimalType decimalType;

        public DecimalIncrSumWithRetractAggFunction(DecimalType decimalType) {
            this.decimalType = decimalType;
        }

        @Override
        public DataType getResultType() {
            DecimalType sumType = (DecimalType) LogicalTypeMerging.findSumAggType(decimalType);
            return DataTypes.DECIMAL(sumType.getPrecision(), sumType.getScale());
        }

        @Override
        protected Expression zeroLiteral() {
            return literal(0);
        }
    }
}